Bladed shear reducing mill



April 26, 1949. H. G. LYKKEN ETAL BLADED SHEAR REDUCING MILL 3 Sheets-Sheet l Filed Feb. 28, 1944 VVENTOES HENRY G. L YKKEN [L/ MM L fh/KEN QB cud, y fw/1.2,

Avv-omver@- 'Patented pr. 26, 1949 UNITED STATES PATENT orrica BLADED SHEAB BEDUCING MILL Henry G. Lykken and William H. Lykken, Minneapolis, Minn.

This invention relates to apparatus for reducing material, particularly of organic or vegetable origin such as grain and seeds to our; pods, shells, hulls, dried vegetable matter, including saw dust to vegetable meals, iiours and fillers; and 'any material having a resilient or toughness resistance to fracture, necessitating a shearing or clipping action to obtain effective and emcient reduction in particle size.

The invention' relates more particularly to apparatus in which the reduction of the material is effected by a shearing and clipping action resulting from the fast-moving particles striking stationary shearing or cutting edges and then on the rebound being struck by fast-moving shearing or cutting edges in repeated sequence under controlled conditions to produce the desired amount of reduction, varying 'from comparatively coarse meal toflne powder such as by breaking the starch cell to produce free starch which is soluble in cold water.

' it is an object of the invention to produce an apparatus adapted for reduction of such material to any particle size by readily effecting changes in number, type and spacing of blading, in number type and spacing of cutting edges and controlled material flow through the apparatus.

These and many other objects are inherent in the apparatus herein illustrated, described and claimed.

The invention is illustrated with respect to the drawings in which,

Figure l is a side elevational view of the pulveriaing mill, partly in section and partly broken away to illustrate the interior construction thereof;

Figure 2 is a partial plan view showing the top of the mill illustrated in Figure 1; v

Figure 3 is a fragmentary sectional view taken along the line 3-3 of Figure 2, illustrating the material and atmosphere controlling portions of the apparatus;

Figures 4 and 5 are enlarged fragmentary plan views of the stationary and rotating elements of the mill shown in Figures 1 and 3;

Figures 6, 'i and 8 are fragmentary sectional views illustrating various arrangements of stationary and rotating elements of the mill illustrated in Figures 1 and 3; and

Figures 9, 10, 11, 12, 13 and 14 are illustrative sectional views of various types and arrangements of stationary and rotating blading. Figures 9-14 are the sectional views taken along a sectional line through the machine, such as that represented by the sectional line Il-IS of Figure 7.

It is to be understood of course that Figures 9-14 are not sectional views of Figure 7 specifically.

Throughout the drawings, corresponding numerals refer to the same parts.

Referring to the drawings, Figures 1 and 3, the pulverizlng mill of the present invention includes a sub-base generally designated IIJ, which may conveniently be of cylindrical construction, equipped with a floor flange II and e. bearing plate I2. The cylindrical base Iii may be out away as illustrated at i5 so as to allow the drive belt or belts to extend into the base so as to run over pulley IE, where a belted connection is used. In Figure l the base Ill is of welded or riveted construction, but it is to be understood that a cast construction or other suitable construction may be utilized, if desired.

Upon the bearing plate I2 there is mounted an intermediate frame member generally designated IB having a lower ange I9 which is bolted to the bearing plate I2 by means of through bolts 20, Intermediate frame I8 has openings 22 and 23 at either side thereof so as to allow air to circulate into the interior of the intermediate frame for a purpose to be described. Within the frame member I8 there is a diaphragm 25 preferably welded in place and equipped with a central thimble 26 extending into the lower flange 29 of hub 30.

Upon the upper surface of the intermediate frame there is mounted a base plate generally designated 4B constituting the lower end cover of the mill housing. The end cover consists of a lower wall 4i and an upper Wall 42 closed at the periphery by means of a circular outer wall 43. The outer wall is cut away at one part so as to provide for the outlet port 44 which is equipped with a flange 45 for convenient attachmen-t of a discharge duct of the mill. Upon plate 42 there is mounted an outer cylindrical shell 50 of the machine which, for convenience, is made in two or more sections bolted together at anges 5I and 52 by means of bolts 53. Shell 50 has bottom flange 54 which is attached to the upper plate 42 of the basie by means of the bolts 55 and a top flange 58 which is attached by means of bolts 6I to a cover plate 60 of the machine.

The cover plate I2 and the bearing plate 60- are each provided with bearing housings for the rotating element of the mill. Thus plate I2 is provided with a bearing housing 62 which is attached at a. central opening 63 of plate I2 by means of studs 64. The bearing housing 62 is provided with a cover plate 61 which is attached to the housing by means of studs 68, the cover ally designated 15 and is held in place by means of a locking nut 1S. The locking nut is preferably equipped with a downwardly extending oil slinger skirt 11 which extends below the upper surface 10 of a central enlargement 18. in the lower wall of the bearing housing. The space within the housing serves as an oil reservoir from which oil cannot easily ow because of the wall 19 on the center of the base. It is to be understood, of course, that the enlargement 19 of the base of the bearing housing 62 and the thickened central portion of the cover 61 are bored out so as to allow a slightclearance in respect to the correspgnding portions of the shaft 1d.

The cover plate 00 is provided with a ringshaped auxiliary plate 8% which is riveted or otherwise attached in concentric relation with respect to the central opening 0@ in the cover plate so as to form a circularlnotch into which the flange 81 of the upper bearing housing generally designated 90 is received. The ange 81 is firmly held in the housing by means of studs 92 and the bearing housing is thus irmly attached to the cover.

The bearing housing 90 is provided with a cover e3 which lsheld in place by studs @t and serves as a connection for the hoisting eye @5. Within the housing there is a recess 90 in which there 4 i tween the spokes H0, as indicated by arrows l and into the interior of cylinder |21; The air continues along the path indicated by arrows |36 past the webs |28 and through the annular space between cylinders |20 and |21 and thence outwardly between the flanges and H2 into the space between diaphragm .25 and lower wall 4|,

as indicated by the arrows |32 and through the openings `21 to the exterior. Interior radiall fan blading may be included between the hub l2@ and the inner surface I 23 of the shaped ange |22 and spokes |I0. and/or the webs between rims and ||2 shaped like fans, if desired, so as to produce a'fan action further enhancing the\ow of air'fromthe interior of cylinder |21 intmthe annular space between the cylinders |25 and |21.' However, for the most part the centrifugal forces on the air are ordinarily suicient to cause the air to ow through the path described. The

cooling air may be precooled below ambient teln-l peratures, if desired to accentuate vthe cooling' eect, where particularly heat sensitive materials are being handled in the mill.

Upon the exterior of cylinder |25 thereA is mounted an end ring |35 of fairly heavy construction which forms a seat for the stack of blading, and then throughout a portion or all of the exterior surface of the cylinder |25 there arealtery nately stacked -blade rings generally designated is positioned a ball bearing assembly 98. the latter being fastened to the upper end of the shaft it by means of the retaining nut 99. Beneath the ball bearing assembly there is provided an oil slinger ring |00 which extends down alongside the central boss |0| formed in the intermediate wall |02 of the bearing housing. Below the intermediate wall there is an additional space it which is vented to the exterior of the bearing housing' by means of the port |06 so as to permit any oil drainage that might escape to drain to the exterior of the machine rather than to enter into the interior thereof. The lower wall |05 of the bearing housing is recessed at |06 and in the recess there is positioned an oil retainer ring lill of felt, spring-pressed leather or other conventional design, held in place by means of the studs |00. Upon the shaft 15 there is mounted a hub 30 having spokes I|0 extending to an inner ange lll, which is in turn connected by a plurality of webs to an outer flange H2. The outer ange ||2 is provided with a peripheral rib H3 to which there is attached a ring 4H4 having mounted thereon a plurality of fan blades H5 which operate in the interior of the fan and discharge cavity between lower wall 4| and upper wall 42 of the base member 40. Upon the upper end of shaft 15 there is mounted a hub |20 which is connected by means of a solid flange 2| to an offset rim |22.'Upon the periphery of the rim |22 there is mounted a sturdy steel shell |25 which ts into the interior of the flange |2 at the bottom of the rotor.- Within the cylinder |25 there is a second smaller cylinder |21 which is fastened to the flange at the lower part of the rotor and is anchored atits upper portion to the outer cylinder |25 by means of a plurality of webs |20.

Within the rotor there a path for cooling air through the openings be- |40 and spacer rings ll in alternate succession, y

spacers are clamped and the stack of rings and in place at the upper end by means of a clamping plate |42 which is held in place by a plurality of studs |43 which thread into the shaped rim |22 of the upper hub. 'I'he studs |43 are preferably recessed into the clamping plate |62, and maybe of the lhexagonally headed type or the type having'a hexagonal recess in the'uppermost face of the head.

Within the cylindrical shell 50 there are likewise stacked a plurality of stationary blade rings generally designated |45 with qspacer rings between successive blade rings, -all held in place between plates 42 and $0 of the outer housing.

Referring to the enlarged views in Figures 4-14 therev are illustrated fragments of the rotary andv stationary blade structure.' As shown in Figures 4 and 5 the rotary blade |40 has a diameter such that clearance is aiorded at |41 between the tips stationary spacer rings ltd.

of teeth v|48 and the The internal diameter of the ring constituting the stationary blade ring |45 is shown at |49 and is preferably such that an overlap of distance is provided between the root diameter of the notches |50 in the rotary blading and the interipr diameter of the stationary blade |45. Likewi'e the notches |5| of the stationary blading |45 ape! of such a depth in respect to the crest diameter of the rotary blading |40 that an overlap of distance "0 is provided.

The notches |50 in the rotor blading and notches I5| in the stationary blading may be round-bottomed, as illustrated, or of any other desired configuration and a small or large nuimn ber of notches may be provided throughoutthe periphery of the blading, ,depending -upon the service in which the pulverizing mill is used. For

certain types of material being pulverized, it is' preferable to have `a large number of small notches, as illustrated at |50 and |5| in Figure 5, while for other types of pulverizing or grinding the small number of larger notches may be utilized, as in Figure 5.

The thickness of the stationary blades |45 and spacer washers |46 in respect to the rotary blades narrow spacing. as shown at the bottom of Fig` ure 6, or the stationary and rotary blading may be arranged in a uniform spacing, as illustrated in Figure 8. As shown in Figure '1, it is desirable, in some instances, to provide a wider clearance at |53 between the upper part of the rotary blade |46 and the next higher stationary blade |45', than at |54 between the lower part of the same rotary blade and the next lower stationary blade |45". For many pulverizing operations the clearance between the rotary blades |45 and the stationary blades |45 is but a few thousandths of an inch, as illustrated in exaggerated form in Figure 8. The rotary blades |45 may have the same or a different number of notches as the stationary blades associated with them. In all of the rotary and stationary blading, however, the notches define sharp edges which provide for a clipping or shearing action upon the particles engaged.

Referring to Figures 9-14 there are illustrated several modications for stacking the rotary and stationary blading. In Figures 4 9 the rotary blades are illustrated at |46, whereas the stationary blades are illustrated at |45. Arrows |55 illustrate the direction of rotation of the rotary blades with resct to the stationary blades. It will be observed in Figure 9 that each succeeding stationary blade from bottom to top in the stack is spaced backward in respect to the direction of rotation, as indicated by the line 656-456. The feeding of materials through the blading is somewhat enhanced by this arrangement. In Figure lil the stationary blades M5 are stacked so that the notches in the blades are directly over each other as indicated by the line i51|51 thus providing a. somewhat slower feeding of the material through the blading. In Figure l1 the stationary blades it are stacked so that each lower blade is positioned backward in respect to the direction of rotation, as' indicated by the line |58-|58, thus providing the slowest feed of material through the mill. In all of the Figures 9-14 the general direction of the material flow through the anill is denoted by arrows |66, but this should not be understood to represent the movement of any one particle of material.

Figure l2 illustrates the sectioning along the lines it-i of Figure 6 and illustrates the decrease in clearance between the rotary blades and the stationary blades from top to bottom in the mill. Thus, at the upper part of the mill there is a relatively wide clearance between rotary blades |40 and adjacent stationary blades |45, as illustrated at i6 I, while the clearance is decreased at the next lower blade, as illustrated at |62, and is a minimum at |63. The dimensions given are, of course, merely illustrative.

In Figures 13 and 14 there are illustrated compound rotary and stationary blading. Thus, in Figure 13 the rotary blades generally designated |45 are composed of two plates |65 which are sharpened so as to present knife edges at |65. The blades are then assembled in the manner illustrated and as a result material fed through the mill in the general direction of arrow |60 is subject to impacted cleavage at knife edges |66. In Figure 13 the stationary blades |45 have straight-cut notches, as' previously described. In Figure 14 the stationary blades |45 are composed of two elements |61 which are sharpened so as to present knife edges |66 and |69 while the rotary blades |40 are of the type having straight cut teeth, as previously described.

6 The type of blading chosen, the number of teeth, the number of teeth on the rotary blading as compared to the number of teeth on the cooperating stationary blading. the angularity of cut of the notches, whether straight cut or sharp edge cut, the clearance, blade material and other factors, all depend upon the type of material being pulverized, the degree of iineness desired and other conditions..A In all instances, however, the sharp corners of the teeth provide eillcient cutting edges which shear and clip the particles undergoing milling. When wear occurs the notches may be recut or ground so as to present fresh sharp edges so as to maintain the efficiency of the mill.

Referring to Figure 1 it will be observed that the upper four stationary ring blades |450. |4517, |45c, and |45d have successively decreasing internal diameters until, as illustrated for the live stationary bladings. the internal diameter reaches the amount .described with reference to Figures 4 and 5. The passage of material through the mill is thus facilitated through the first several courses of rotary or stationary blading, and thus facilitates ow at a time when the pulverization of the material may not yet be sulciently great to facilitate uid flow of the material in air or other gaseous dispersion.

In Figure 1 the feed of the dry material is by means of a worm-feeding apparatus best shown in Figures 2 and 3. The worm feeding apparatus consists of a base plate |10 to which there is mounted a cylindrical member |1| provided at its outer end with a flanged hopper |12. The cylindrical member is provided at each end with a closure plate and bearing assembly generally designated |13 which serves rotatively to sup-f' port the worm shaft |14'having on it the enlarged worm-carrying section .|15 wherein the feed worm itself is designated |16. Dry material is fed into the hopper at |11 and is forced endwise by means of the worm until it reaches the discharge port ila where the material falls through an opening |19 in the top plate 60 of the mill and directly onto the uppermost rotary blade |40. The cylindrical member |1| of the dry material feeder is provided with an oilset nipple having a screw cap |6| which may be removed, as desired, for inspection and also to permit a predetermined quantity of air to flowthrough the mill. Additional air or inert gas inlets are provided in the top cover 56, as shown at |82, each being provided with a removable cap |83.

In operation, a mill of the type illustrated in Figure 1 is first brought up to speed by suitable power drive to V-belt pulley i6. Air, which may be precooled if desired, is drawn into the interior of the rotor structure as previously described and is scrubbed along the inside surface of the cylinder |25 and thence is discharged through ports 21 beneath the lower wall 4| of the base plate 46. The dry material being pulverized is then fed into the machine by means of the feeding apparatus, which is suitably driven at slow speed and one or more of the caps Ill-|83 are removed so as to permit a predetermined amount of air to be drawn into the mill for facilitating a ow of the dry material therethrough. If desired, inert gases may be conducted to the nipples |80|82 in the event the material undergoing pulverizing is sensitive to oxidizing conditions. Only enough air or inert gas is admitted into the mill to permit the formation of an apparent fluid composed oi' the material being pulverized and the air or'inert gas. If desired, the air or inert gas so admitted may be precooled so as to maintain the material being in much the same manner as real fluid such as water or oil. As the solid material enters the region of the rotary and stationary blading, it is subjected to progressive reduction in particle size by repeated shearing and clipping action as the individual particles are brought into contact at high speed with the sharp edges of the stationary and rotating teeth. As a result exceedingly fine pulverizing can be obtained. For ex ample, by utilizing the apparatus of the present invention it is possible to obtain starch particles of almost colloidal dimensions with the result. there is obtained starch which is soluble in cold water. Heat sensitive material, for example cocoa, resins and the like, may readily be pulverized without damage. due to the fact that cooling air is supplied and scrubbed against the interior of the mill rotor, and because the air or gas admitted may be pre-cooled, with the result that excessive temperature rise is prevented. The air or gas admitted may be inert to the material being treated. Thus, with some materials, carbon dioxide or carbon monoxide may be used, whereas with other materials there may be used nitrogen or rare gases such as helium.

The pulverized material discharged from the lowermost of the rotary bladings passes into the annular fan housing formed by plates l and l52-"of the exterior wall 453 and is discharged out wardly through port M by the action of plates H5. The entire movement of the solid material and suspending gases through the mill is due to the fan action produced by fan blades H andl the amount of air or gasdrawn through the mill may thus conveniently be adjusted by regu lating the number and sizes of the openings at nipples l8I-l8.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that we do not limit ourselves to the specic embodiments herein except as defined by the appended claims.

What we claim is:-

1. A mill comprising a cylindrical frame closed at one end, journals mounted on the frame coaxially with the cylindrical frame, a shaft rotatably mounted in the journals, a, solid flange on the shaft near the closed end of the cylindrical frame, a hollow cylindrical rotor of a diameter smaller than the inside of the cylindrical frame .and having a length shorter than said frame and mounted on the solid flange for rotation therewith, a flanged wheel relatively open adjacent its center mounted on the shaft and supporting the other end of the hollow cylindrical rotor, an internal cylinder having a length shorter than the cylindrical rotor mounted on the flanged wheel and positioned concentrically within the cylindrical rotor so as to form an inner axial path for gases in the direction of the shaft and towards the closed ange from which the end of the internal cylinder is spaced, a diaphragm 8 kmounted at right angles to the shaft and adjacent the anged wheel, said diaphragm having an inturned auge at its center of a diameter and positioned so as to form an air -path entrance through the relatively open-centered wheel to the interior of the internal cylinder, said flanged wheel also being provided with openings in its flange and located at a' diameter so as to be between the cylindrical rotor and internal cylinder. forming a path for the discharge of gases owing axially between said cylinder, and cooperating lmilling elements mounted on the inside of the cylindrical frame and on the outside of the cylindrical rotor and projecting into the space therebetween.

2. An apparatus of the type set forth in claim li further characterized in that the flanged wheel has radially spaced inner and outer circumferential ilanges with openings therebetween and supported by an integral spider mounted on the shaft, the inner circumferential flange being of a diameter so as to nest with and support the internal cylinder and the outer flange being of a diameter so as to nest with and support the cylin drical rotor.

3. The apparatus of claim l further characterized in that the iianged wheel has blower blading mounted thereon and the cylindrical frame includes a fan space for said blading to form a fan being open axially to the space between the cylindrical frame and rotor to receive milled material and a carrier duid therethrough, said fan space being provided with a radial outlet.

4. The apparatus of claim 1 further characterized in that means is provided to produce a suction on one end of the space occupied by the milling elements, the frame being provided at its opposite end with a solid material feed into the space occupied by the milling elements and aperture means leading into said space, said aperture means being capable of being opened to regulated amounts for the inow therethrough of? carrier fluid along with the solid material fed.

5. A mill comprising a hollow frame of circular interior cross-section, milling elements mounted on the interior of said frame, a rotor journaled in the frame, said rotor being hollow, of circular cross-section, and smaller than the frame so as to allow a, space between the rotor and the frame, said rotor being open at one end and closed at the other end, milling elements mounted on the exterior of the hollow rotor in cooperating relationship with the milling elements mounted on the interior of the cylindrical frame, an inner cylindrical duct of relatively large diameter extending into the hollow rotor and spaced endwise a short distance from the closed end thereof and similarly spaced from the inside of the rotor, and duct-work on the frame for introducing air into the inside of the inner cylindrical duct for ow axially thereof in a direction towards the closed end of the rotor and thence outwardly and into the space between the outside of the duct and the inside of the rotor; for reverse flow axially be- HENRY G. LYKKEN. WILLIAM H. LYKKEN.

(References on following um) cooperatively receiving: chamber, said chamber for discharge of'cooling y ille of this patent:

Number summons crrm, 11mm ara., The following references are of record in the 1,977,955 ''"5' ,1 ,766 UNITED STATES PATENTS 2,189,338 Name Dite 2,204,140 Russen May 17. 1859 2,255,213 Joslin July 3, 1860 Bearly Nov. 14, 1865 l. Greenleaf Feb. 18, 1868 Number Bell Oct. 23, 1883 28,826 Day Aug. 6, 1907 530,253 Bausman Nov. 18, 1919 341,317 Green Feb. 24, 1931 u 444,684

Name Date Albert Jan. 12, 1932 Robinson Oct. 23, 1934 DeBethune Apr. 13, 1937 Francis Jan. 18, 1938 Ditto Aug. 15, 1939 Langbeln June 11, 1940 Good Sept. 9, 1941 FOREIGN PATENTS Country Date Germany May 3, 1884 Germany July 24, 1931 France June 6, 1904 Great Britain Mar. 25, 1936 

